[General practice trial with breath alcohol analysis]

Breath- (BrAC) and blood-alcohol concentrations (BAC) of 42 persons are compared in a drinking experiment under conditions which approach the situation in practice. Breath-alcohol determinations consisted in double measurements and included the determination of temperature of expired air. The measured BrAC was related to a temperature of 34 degrees C and was interpolated to the time when the blood sample was taken. According to the fact that in most cases the resorption of alcohol was not yet finished, the BrAC converted by a factor 2.1 to blood equivalent values were remarkably higher than the corresponding BAC values. If only these values are taken into consideration which are measured in the period of more than 20 minutes after drinking was stopped, the converted BrAC values differ not more than +20% from BAC values.